Fluid Inclusion Investigations of the Masjed Daghi Copper-Gold Porphyry-Epithermal Mineralization, East Azerbaijan Province, NW Iran

The Masjed Daghi mineralization is located 30 km southeast of Jolfa city at the bank of Araxes River, northwest Iran. This area is situated in the Alborz-Azarbaijan structural zone of Iran. The most widespread rocks in the mineralization area are andesite and trachyandesite, while there are rock units of latite tuff, andesitic agglomerate, and hornblende porphyry basalt in eastern hills and Eocene flysch in the southern part of the area. Several intrusive bodies are present in the study area, from which the dominant intrusive rock hosting the mineralization is diorite porphyry. The mineralized rock units of the area are cut by different diorite ad mafic dikes. The most prevalent texture of mineralization is dissemination, while open space filling textures including veins and veinlets, are common as well. Diverse types of alteration including potassic, phyllic, argillic, silicification, and a little of carbonatization were recognized in the field and microscopic observations as well as by XRD. In addition to thick silica veins and stockwork zones, some silica, barite, sulfide, and calcite veins and veinlets have occurred in the Masjed Daghi mineralization area. In this research, 26 doubly polished thin sections (wafers) were prepared and investigated. Four samples were taken from surface veins, while 22 samples were chosen from core samples (of 6 boreholes) of white and grey-white silica, and silica-barite veins. The fluid inclusion studies on 105 primary fluid inclusions indicated five phases for inclusions including: 1) liquid or gas, 2) liquid and gas, 3) liquid, gas, and solid, 4) liquid, gas, halite, and solid, and 5) liquid, gas, halite, and two types of solids. The data gained from fluid inclusions approved two mineralization fluids which caused porphyry and epithermal mineralizations. The porphyry fluid inclusions were homogenized in temperatures of 122°C to 550°C with a maximum of 700°C and average salinity of 55 wt% NaCl equivalent, while the epithermal inclusions indicated an average homogenization temperature of 186°C with an average salinity of 6.23 wt% NaCl equivalent.

The first discovery of Xinlong epithermal gold deposit in southern margin of the Bangonghu-Nujiang metallogenic belt: A new expansion of gold prospecting in Northern Tibet

The Xinlong gold deposit is located in Niyma County,Naqu area of Tibet and was discovered by the Institute of Mineral Resources,Chinese Academy of Geological Sciences through the 1∶50000 mineral geological survey.The ore bodies occur in the Zenong Group volcanic rocks in the middle section of the central Lhasa subterrane and are structurally controlled by the NNW-striking faults.Four ore bodies have been found,exhibiting cloddy,dense-sparse,disseminated,and breccia structures.The ore minerals are mainly tetrahedrite group minerals,and other ore minerals include pyrite,chalcopyrite,nevskite,bornite,anglesite,native gold,and silver-gold bearing selenide,etc.The types of alteration are dominated by silicification,as well as middle-and high-graded argillization.The alteration mineral assemblages contain quzrtz,pyrophyllite,and kaolinite.The Zaliela Formation volcanic rocks of Zenong Group are silicified by later hydrothermal fluid with vuggy quartz in some fractured zones.The middle-and high-graded argillization are characterized by pyrophyllitization and kaolinization.The Xinlong gold deposit shows great metallogenetic potentiality and has been revealed by 1∶10000 geological mapping,IP sounding,and trial trenching in the mining area.Combined with the regional metallogenic geological setting,we suppose that a potential epithermal gold belt probably exists in the middle of the Lhasa terrane.The discovery of the Xinlong gold deposit opens a new chapter for the gold prospecting in Northern Tibet.

Copper and Gold Mineralization Features in Deh Bala Region—South of Takestan

The studied area is located in 30th km of Bouien-Zahra road in Saveh in southern border of Khiaraj 1:100,000 Geology map rectangle (Danesfahan) in South of Takestan of Iran. This area is a part of volcano-plutonic belt of Urumia-Dokhtar. Rocky outcrops in this area are mainly in two types of volcanic and plutonic. Volcanic Rocks with the age of Eocene are Trachyte to trachyandesite and andesite to basalt-andesite. Plutonic stones with the age of Oligo-Miocene to Miocene are in types of quartz diorite, quartz monzonite, Monzonite and Semi-acidic volcanic domes and granite aplite. Due to having dominant fault systems with trends of NW-SE and NE-SW in an intersectional manner in this area, vein-veinlets Siliciclastic sulfide mineralization can be observed in line with the same faults. Monzonite intrusive rocks are considered as host stone of these mineralizations. The information obtained from field observations and laboratory studies confirms the main alteration along with mineralization in types of silicic and pyrite, sericite, carbonate, argillic and propylitic. Mineralogy Paragenesis in the study area includes Pyrite, chalcopyrite, bornite, colitis, malachite, hematite and goethite and the most important Gang minerals including quartz, calcite, albite, sericite, kaolinite, pyrophyllite, epidote, alunite and jarosite, and according to carried out studies, copper, gold and silver are among mineralizing elements and elements such as molybdenum, cadmium, arsenic and mercury show anomalies as accompanying and guidance elements in some of the samples. The grade of copper in this area in sulfide siliciclastic veins is 1% to 3% and the grade of gold is 130 ppm and the grade of silver is reportable from 0.5 ppm to 6 ppm. Based on the geothermometry studies of fluid inclusions, homogenization temperature from 150°C?to 300°C?and the salinity grade from 4 to 5.5 percent indicate the fact that an epithermal hydrothermal system in final stages controls the mineralization of the area.

Characterization of Arroyo Verde Epithermal Deposit:Paragenesis,Mineral Geochemistry,Geochronology and Fluid Inclusions in Lower Chon Aike Volcanism,Argentina

Arroyo Verde epithermal deposit,in the North Patagonia region of Argentina,is located within the Lower Chon Aike volcanism and is developed between 192.6±2.5 Ma(mineralization host rock)and 189.5±2.6 Ma(overlying lava).Marifil volcanic complex is the host rock for these veins,veinlets and breccias.This particular small deposit has developed low to intermediate sulphidation characteristics,with gangue mineral textures associated with several ore minerals.Electron probe microanalysis determines electrum,silver minerals such as acanthite,and tetrahedrite,related Ag-Cu minerals like jalpaite,mckinstryite,stromeyerite,and base metals like chalcopyrite,sphalerite,galena and pyrite.Fluid inclusions in quartz of two out of five events indicate that these Low Jurassic veins were formed due to subtle boiling and dilution mechanisms and by low-salinity(3.4 wt.%to 6.7 wt.%NaCl Eq)magmatic-hydrothermal fluid at 225 to 310℃.The fluid inclusion measurements that indicate boiling(Event 3)were plotted,and based on this data,we interpret that the Arroyo Verde deposit has been eroded between 550 and 700 m.This particular character has not been previously recorded for other sectors of the eastern north Patagonian region.

Geodynamic settings of Mesozoic large-scale mineralization in North China and adjacent areas——Implication from the highly precise and accurate ages of metal deposits

Based on the summary of the highly precise datings of the metal deposits and related granitic rocks in North China craton and adjacent areas, such as the molybdenite Re-Os datings, 40Ar-39Ar datings of mica, K-feldspar and quartz, some Rb-Sr isochrons, and the SHRIMP zircon U-Pb dating and single grain zircon U-Pb dating, we suggest that the large-scale mineralization in North China craton and adjacent areas take place in three periods of 200-160Ma, 140Ma, and 130-110Ma. Their corresponding geodynamic settings are proposed to be the collision orogenic process, transformation of the tectonic regime, and delamination of the lithosphere, respectively, in light of analyzing the Mesozoic geodynamic evolution in the North China craton.

The fluid regime of formation of epithermal ore mineralization in the eastern part of the Aldansky shield (Russian Far East)

IN the eastern part of the Aldansky shield, on the territory of volcanic and sedimentary basins of Proterozoic age, many deposits and ore occurrences of Au, Ag, Mo, U, V, Ni, Co, Ba and Th are revealed.Petrographic, geochemical and fluid inclusion study indicate their low temperature (epithermal) genesis.It is supposed that these ores were formed in the grenville metallogenic epoch (Upper Proterozoic). The epithermal ores in this region are connected with: (i) eisite (apatite-albite metasomatites)and (ii) argilliceous-white mica metasomatites (argillisites and beresites). Apatite-albite metasomatitesare associated with rare-earth ores. As a rule, metasomatite bodies are controlled by steeply-dipping fractures. Albite, quartz and fine-grained hematite form a typical mineral assiciation. The ore bearing metasomatites were formed at pH = 4 and T≤300℃. The beresite type argillaceous-white mica alterations are widespread in volcanic rocks of the Ulkansky basin and in the sedimentary suites of the Uchursky basin. They are distinguished on all stratigraphiclevels, but especially often in a zone of structural-stratigraphic unconformity (SSU) of AR-PR. Au, Ag,Mo, V and U deposits and occurrences are connected with this type of alterations. Their structural pos-

Alkalic-type epithermal gold mineralization associated with Tongshi complex in Pinyi County, Shandong Province

THE alkali-rich subvolcanic complex of Tongshi and the associated gold mineralization are located at thesouth boundary of Pinyi Mesozoic volcanic depression in western Shandong Province. There are morethan 30 gold deposits and mineralization locations around the complex, in which Guilaizhuang gold deposit and Zhuojiazhuang bonanza gold deposit with important economic value are included. This area isbecoming a perspective target of superlarge gold deposit. In the mine area, there crop out Archeangranitic gneisses, Paleozoic carbonates and Jurassic clastic rocks, which was intruded by Tongshi complexwith 30 km. The complex consists of K-high igneous rocks formed by two stages of magmatism. In thefirst stage, the monzonitic dioritic porphyrys, which belong to K-high calc-alkalic rocks, were formed andin the second stage, monzonitic-syenitic porphyrys, which belong to K-high alkalic rocks, were formed.Their Ar-Ar ages are 189 Ma and 188 Ma, respectively. At the end of the second stage, a lot of theexplosive breccias were formed. The gold mineralization in this area is closely associated in time andspace with the second stage monzonitic-syenitic porphyrys. Based on the characteristics of

The relationship between epithermal and low temperature mineralizations

THE term epithermal as a kind of hydrothermal mineralization was first used by Lindgren in 1933. It describes those ore-forming systems occurring at depths mainly less than 1 km, and at temperatures less than300℃. Epithermal deposits of Cenozoic ages are widely distributed in the Circum-Pacific belt, especiallyin the Southwest Pacific area. From the 1980s on, the study of epithermal ore deposits became an important field of mineral deposit research. Hayba et al.and Hedenquist classified the epithermal systemas adularia-sericite or acid-sulphate types, and low sulphidation or high sulphidation types, respectively.The low temperature mineralization, which was exemplified by the deposits in southwest China, refers tothe system at temperature mainly less than 200℃. Besides the distinction in temperature, however, thereexist many differences between epithermal and low temperature mineralizations.

Carbon Dioxide Mineralisation and Integration with Flue Gas Desulphurisation Applied to a Modern Coal-Fired Power Plant

For Finland, carbon dioxide mineralisation was identified as the only option for CCS （carbon capture and storage） application. Unfortunately it has not been embraced by the power sector. One interesting source-sink combination, however, is formed by magnesium silicate resources at Vammala, located -85 km east of the 565 MWe coal-fired Meri-Pori Power Plant on the country＇s southwest coast. This paper assesses mineral sequestration of Meri-Pori power plant CO2, using Vammala mineral resources and the mineralisation process under development at Abo Akademi University. That process implies Mg（OH）E production from magnesium silicate-based rock, followed by gas/solid carbonation of the Mg（OH）2 in a pressurised fluidised bed. Reported are results on experimental work, i.e., Mg（OH）2 production, with rock from locations close to Meri-Pori. Results suggest a total CO2 fixation capacity -50 Mt CO2 for the Vammala site, although production of Mg（OH）2 from rock from the site is challenging. Finally, as mineralisation could be directly applied to flue gases without CO2 pre-capture, we report from experimental work on carbonation of Mg（OH）2 with CO2 and CO2-SO2-O2 gas mixtures. Results show that SO2 readily reacts with Mg（OH）2, providing an opportunity to simultaneously capture SO2 and CO2, which could make separate flue gas desulphurisation redundant.

福建紫金山矿田悦洋银多金属矿床银的赋存状态和沉淀机制

浅成低温热液矿床是世界上银矿的重要矿床类型,伴生有金铜铅锌等多种金属。银的赋存状态研究可以为矿床资源禀赋、选冶成本以及经济价值的综合评价提供重要的依据。近年来,矿物自动定量分析系统越来越多地应用到贵金属的赋存状态研究中,相比传统方法而言其能提供精确定量的矿物学信息。悦洋银多金属矿床位于福建省紫金山矿田,是典型的浅成低温热液矿床,是研究银赋存状态的理想选区。通过野外地质调查研究发现,矿体主要受控于岩性边界和断裂构造,主要矿石类型为热液角砾岩型和石英脉型。成矿作用可以分为石英-黄铁矿、石英-黄铁矿-黄铜矿、石英-银多金属、石英-碳酸盐等四个阶段,其中银在石英-银多金属阶段沉淀,可以进一步划分为石英伊利石硫化物亚阶段和石英冰长石硫化物亚阶段。本文在野外地质调查的基础上,针对不同的矿石类型使用TIMA(TESCAN Integrated Mineral Analyzer)自动矿物分析系统,结合显微镜下观察、扫描电镜和电子探针分析手段,对银的赋存形式和分布情况进行了定量化研究,根据矿物共生组合对银沉淀机制及成矿过程进行了探讨。研究结果显示,悦洋矿床中的银90%以上以独立矿物的形式存在,主要是硫化银和自然银,且粒径大多在10~50μm之间;少部分银以次显微包裹体形式存在于黄铜矿中,或以显微包裹体和类质同相形式存在于黄铁矿和闪锌矿中。成矿热液中银主要以硫氢络合物形式运移,主成矿期大量的冰长石与银矿物共生表明沸腾作用是主要的沉淀机制。

试论中亚造山带东部多宝山矿田斑岩铜浅成低温金系统成矿特征与矿床模型

多宝山矿田位于中亚造山带东段,是目前我国东北地区规模最大、成矿时代最老(477~470 Ma)的斑岩铜钼浅成低温热液金成矿系统,已探明铜、钼、金储量分别可达5 Mt、0.16 Mt和130 t。从成矿系统角度,其成矿特征和矿床模型尚不清晰。本文系统分析了矿床的地质地球化学特征和成矿时代,发现该成矿系统存在两期成矿事件,以第一期为主,发生在早奥陶世;第二期为叠加成矿,发生在晚三叠世。成矿作用具有下部为隐爆角砾状铜矿化、中部为脉状铜矿化、上部为金矿化的空间结构特征,围岩蚀变从中心向两侧依次为钾化黑云母化带、青磐岩化带、黏土化带、碳酸盐化带、绢英岩化带和硅化带。成矿流体主要来源于岩浆水,从多宝山斑岩铜矿到争光浅成热液金矿床呈现大气水加入比例增大的趋势。根据第一期成矿斑岩具有高Ce^(4+)/Ce^(3+)(174~461;均值约290)、高f_(O2)埃达克质岩浆特征,进一步得出主成矿期与古生代古亚洲洋俯冲作用相关的壳幔混源岩浆作用有关。成矿受古火山机构所制约,其北西到南东成矿深度增大与剥蚀程度相关,受铜山逆断层作用效应,暗示铜山断层以南为较好的找矿靶区。最后,本文建立了该区古生代斑岩铜浅成低温热液金成矿系统的矿床模型,以期为该区进一步矿产勘探提供借鉴。

山西省吕梁山黄圈塔铅锌矿地质特征及找矿方向

黄圈塔铅锌矿位于吕梁碳酸盐台地的柳林背斜北翼,铅锌矿体主要赋存于下奥陶统三山子组和中奥陶统马家沟组碳酸盐岩中,蚀变和铅锌矿化产于NW向断裂破碎带中。通过对该矿床地质特征、地球物理特征、地球化学特征、矿化蚀变特征的综合研究表明,铅锌矿体主要赋存于NW走向的F1断层破碎带中,矿化以裂隙交代充填型为主,次为蚀变岩型;目前控制有2条铅锌矿体,其中以2号矿体为主,激电测深剖面显示极化率异常向下未封闭,指示深部(埋深150 m)存在极化地质体;勘查区地表未发现与成矿有关的火成岩;矿化成分较为简单,金属矿物主要是方铅矿、闪锌矿,脉石矿物为方解石、白云石,围岩蚀变为中低温矿物组合;矿床成因类型应属中低温热液型铅锌矿床。基于激电测深剖面资料,有必要进一步开展矿区深部找矿工作。

Tracer system on halogen mineralizer from the epithermal deposits in Guizhou Province

HALOGENS are typical mineralizer elements and play a very important role in remobilization and resettlement of the ore-forming mental elements in the hydrothermal deposits. Studies of tracer system on halogens mineralizer include the following aspects: (i) halogens’ role as mineralizer in ore-forming action;(ii) halogens importance as tracer elements in formation and evolution of the epithermal ore deposit;(iii) halogens’ significance as guidance in looking for the buried orebodies. Guizhou is a concentrated area of epithermal Hg, Sb and Au deposits, where are distributed famousepithermal deposits such as the Wanshan Hg deposit, the Banpo Sb deposit, the Danzhai Hg-Au depositand the Lannigou Au deposit. Many researches into geological and geochemical characteristics of thesedeposits have been done, but few study on halogen mineralizer.

埃达克质岩与Cu-Au成矿作用关系的初步探讨

近来的研究发现,埃达克质岩与Au、Cu、Mo等浅成低温热液矿床及斑岩矿床有密切的关系。我们的研究表明:(1)我国的斑岩铜矿大多与埃达克质岩有关,如德兴、沙溪、多宝山、乌奴格吐山和新近发现的东疆土屋斑岩铜矿等,有些被划归与富碱侵入岩或A型花岗岩有关的斑岩铜矿,如玉龙,也具有埃达克质岩的地球化学特征;(2)华北地区的Au矿床大多与埃达克质岩有关,最典型的如胶东和小秦岭;(3)长江中下游地区的Cu、Au、Mo矿床的岩浆岩大多为埃达克质岩。埃达克质岩与成矿作用之所以密切相关,其原因在于它们在地壳深部形成的条件和环境类似,这就为Au、Cu、Mo等的找矿开辟了一个 新的思路。埃达克质岩浆是玄武质岩石在高压、高温和含水条件下熔融形成的,上述条件有利于Cu、Au、Mo等金属元素溶解进入熔体。关于找矿方向,文中指出3点:(1)埃达克质岩发育的地区可能是矿床聚集的地区;(2)与消减作用有关的埃达克岩更有利于成矿元素的富集,对于中国来说,晚元古宙-古生代的古亚洲洋造山带内消减作用广泛发育,有巨大的找矿前景;(3)找矿工作应围绕埃达克质岩体及周围地质体进行。

东胜砂岩型铀矿床低温热液流体的证据及意义

东胜地区砂岩型铀矿床是近年来发现的大型砂岩型铀矿床。笔者首次发现了低温热液流体成矿作用的证据:矿体中有后生的钛铀矿和锐钛矿组合。矿石流体包裹体均一温度为58～176℃,平均114.9℃。研究表明,鄂尔多斯盆地在中晚侏罗世—白垩纪发生过显著的构造热事件,造成砂岩型铀矿含矿层之下产生大量的微裂隙与裂隙带的出现,导致下部热液流体向上运移。低温热液流体的成矿作用是形成东胜铀矿床的重要因素。

西藏铁格隆南超大型铜(金、银)矿床地质、蚀变与矿化

铁格隆南是班公湖-怒江成矿带西段重要的斑岩-浅成低温热液铜(金、银)矿床,也是西藏地区首个铜资源量超过1000万吨的超大型铜(金、银)矿床,其蚀变与矿化结构的精细解剖,对完善区域成矿理论和指导找矿实践有重要的指导意义。文章基于详细的野外地质调查、钻孔编录和镜下鉴定,识别出铁格隆南矿床具有斑岩和浅成低温热液叠加成矿作用特征。其中,斑岩成矿作用主要位于矿床深部及外围,以细脉状、脉状、浸染状黄铁矿、黄铜矿、斑铜矿及少量辉钼矿等为主,蚀变为钾硅化、青磐岩化、黄铁绢英岩化,发育A、B、D型脉体。浅成低温热液成矿作用主要产于矿床中-浅部,叠加于斑岩成矿作用之上,以浸染状-脉状黄铁矿、硫砷铜矿、斑铜矿、铜蓝、蓝辉铜矿、斯硫铜矿、雅硫铜矿、久辉铜矿等Cu-S体系矿物为特征,蚀变为高级泥化,广泛发育N脉(即高岭石或明矾石-硫化物脉)。蚀变、矿化特征及脉体穿切关系揭示,矿床成岩成矿作用可细分为岩浆期(Ⅰ)、岩浆-热液期(Ⅱ)和表生期(Ⅲ)。成岩成矿年代学结果揭示,矿区内闪长玢岩侵位时代较早(123 Ma),代表岩浆活动上限;花岗闪长斑岩(122～120 Ma)是主要的含矿斑岩,与成矿作用关系最为密切;火山岩覆盖于地表,喷发时代较晚(111 Ma),代表成矿后岩浆活动的产物。钾硅化的黑云母和黄铁绢英岩化的绢云母40Ar-39Ar年龄分别(121.1±0.5) Ma、(120.8±0.9)Ma与斑岩成矿作用的辉钼矿Re-Os年龄((121.2±1.2) Ma)一致,而高级泥化的明矾石40Ar-39Ar年龄为(117.9±1.6)Ma与浅成低温热液矿化的黄铁矿Rb-Sr年龄((117.5±1.8)Ma)一致。所以,依据时空关系,铁格隆南超大型矿床成矿作用可细分为岩浆热液成矿作用(123～119 Ma)、浅成低温热液成矿作用(118～117 Ma)和火山岩覆盖保存(111～110 Ma)3个阶段。

高硫-低硫化浅成低温热液矿床的短波红外矿物分布特征及找矿模型——以西藏铁格隆南(荣那矿段)、斯弄多矿床为例

本文以铁格隆南(荣那矿段)高硫化浅成低温热液矿床和斯弄多低硫化浅成低温热液矿床为研究对象,运用短波红外技术快速厘定了上述两个矿床的蚀变矿物类型及组合特征,构建了基于短波红外勘查技术的找矿模型。研究发现:铁格隆南矿床(荣那矿段)的蚀变矿物垂向分带组合为:高岭石→高岭石+(地开石+明矾石)→高岭石+明矾石+(地开石)→高岭石+地开石+明矾石。由于高硫化浅成低温热液交代黄铁绢英岩化带的斑岩型矿体,致使上部矿石中还有少量交代残余的绢云母;斯弄多低硫化浅成低温热液矿床的蚀变矿物垂向分布为:白(绢)云母+(钠云母)→白(绢)云母+钠云母+(伊利石)→白(绢)云母+钠云母+蒙脱石+伊利石→白(绢)云母+钠白云母+蒙脱石+伊利石,其中顶部白(绢)云母是后期黑云母花岗斑岩蚀变所产生,本身与成矿无关;矿体主要赋存在伊利石+蒙脱石带,随着蒙脱石被伊利石化,矿体也逐渐尖灭。

西藏斯弄多浅成低温热液型银铅锌矿床银的赋存状态研究

斯弄多银铅锌矿床是冈底斯成矿带林子宗群火山岩中发现的首例低硫化型浅成低温热液型中-大型多金属矿床。矿区矿物组合多样,矿石组构复杂,具有热液成矿作用的典型特征,成矿阶段可划分为(I)闪锌矿-黄铜矿-硫砷铜矿-黄铁矿-石英阶段、(Ⅱ)方铅矿-闪锌矿-银矿物阶段、(Ⅲ)黄铁矿-石英-方解石三个成矿阶段。通过野外调查、地质编录、显微观察和电子探针(EPMA)微区分析,本文对该矿床中银的赋存状态进行了详细的研究。结果表明,银主要以独立银矿物形式存在,方铅矿、闪锌矿、黄铁矿、黄铜矿等金属矿物中不可见银极少。银矿物种类主要为硫砷铜银矿、辉银矿、深红银矿、螺状硫银矿和自然银,呈裂隙银或粒间银形式赋存于矿区碧玉、铁锰碳酸盐和早期金属硫化物中,次以包裹银形式赋存于早期硫化物中。另,在硫砷铜矿中发育极少的类质同象不可见银。银矿化主要形成于成矿阶段Ⅱ,银主要以硫的络合物形式运移,随着成矿流体物理化学条件的变化而发生沉淀,形成银矿物。

华南地区中生代主要金属矿床时空分布规律和成矿环境

以广泛地质调查和放射性同位素年龄精测数据为基础,总结提出了华南地区中生代主要金属矿床成矿出现于三个阶段,即晚三叠世（230-210Ma）、中晚侏罗世（170-150Ma）和早中白垩世（134-80Ma）。晚三叠世矿化组合为钨锡铌钽;中晚侏罗世的矿化组合进一步分为170-160Ma斑岩-矽卡岩铜矿和160-150Ma与花岗岩有关的钨锡多金属矿床;白垩纪矿化虽然持续了54Ma,但主要峰期在100-90Ma,主要矿化组合为浅成低温热液型铜金银矿床和花岗岩有关的钨锡铜多金属矿床。晚三叠世钨锡铌钽矿化成因上与过铝质二云母花岗岩有关,是华北、华南和印支三大板块后碰撞过程的成岩成矿响应。在180Ma左右Izanagi板块向欧亚大陆俯冲,于170-160Ma期间可能由于俯冲板片局部多处撕裂而形成Ⅰ型或埃达克质岩石和有关的的斑岩铜矿,紧接着在南岭地区于160-150Ma期间俯冲板块开天窗,软流圈物质直接涌入上地壳,形成了一种壳幔混合型高分异花岗质岩石及其钨锡多金属矿床。在135Ma左右由于俯冲板块改变了运动方向,由斜向俯冲调整到几乎平行大陆边缘沿NE方向走滑,造成大陆岩石圈大面积伸展而形成了大量白垩纪断陷盆地和变质核杂岩,并伴随大规模的火山活动和花岗质岩浆侵位及其浅成低温热液铜金银矿化系统、与花岗岩有关的钨锡多金属矿化系统和热液型铀矿的形成。

德兴大型铜金矿集区的研究进展和成矿模式

德兴大型铜金矿集区是我国最重要的铜金产地之一。多年来,德兴矿集区的成矿过程和成因模式一直引起广大地质学家的广泛关注。在前期大量的野外工作观察和多年研究基础上,结合前人的研究成果,本文提出德兴矿集区由两套成矿系统组成:新元古代金山-水石坞-西蒋-渔塘-蛤蟆石-上洛造山型金成矿系统和燕山期德兴和银山斑岩-浅成低温热液型铜金多金属成矿系统。德兴矿集区的造山型金矿可进一步划分为两个亚系统,分别为对应于区域NW向推覆构造的NWW走向、缓倾斜的金山金矿田超糜棱岩型亚系统(约为840Ma),和对应于区域上NE向走滑剪切运动的NE走向、陡倾斜的蛤蟆石金矿田和金山金矿阳山矿段的石英脉型亚系统(约为750~710Ma)。造山型金矿的成矿物质来自富金的新元古代双桥山群基底地层,成矿流体主要为富CO2的变质流体。燕山期斑岩-浅成低温热液系统的形成时代为约170Ma,此时古太平洋板块开始向华南大陆俯冲,导致赣东北深大断裂活化,引发新元古代形成的富铜金的初生地壳重熔再造,形成德兴Cu-Au-Mo矿和银山Cu-Au-Pb-Zn-Ag矿,成矿热液主要来自于岩浆流体来源的贫CO2的NaCl-H2O体系。